Need Serious advice on cylinders cutting out PLS

[vtr9999]

hi everyone,
i have a 2000 vtr that ran great for years with hindle pipes dynojet and a k and n filter the bike has 28,000km
In the transmission I have changed one shifter fork twice now, i think this pertains to learning how to pull second and third gear wheelies for half a mile
I took the fuel tank and fairings off to be painted and i have had either the front or rear cylinder cutting out ever since.

In the process of trouble shooting we have
cleaned the carbs,
chked vacuum line and petcock diaphram works properly and vacuum line is connected to the right spout
chked vent for fuel tank it is clear
changed plugs, coils, and wires
changed both computers
chked all grounds and wiring
found 5lbs difference in cylinders on compression so we put new rings in,
relapped valves and shimmed to spec
i am waiting on a new regulator and stator then we will have changed all electrical parts
after that i plan to reset the tps and balance the carbs but were past frustration on this one
the bike cuts out intermittently at idle and while on the throttle runs good about two thirds of the time
any advice would be apprecciated, i have fitted motocross bars a 954 front end a ohlins rear shock and it is twice the bike in handling with those mods i just cant stand the cylinder cutting out
tks to any advice in advance Rick

[tattie]

Rick,
Hi from across the water (Sunny Scotland)
It seems like you have done a fair bit of work on the bike, my 97 storm has suffered the same problems, cutting out when ticking over, backfiring through the carbs and ocassionally cutting out on the downchange 3rd to 2nd to 1st, when it starts that, I know it is time to get the carbs balanced. Was the motor cold when you had the clearances done? As I have heard it said that a hot motor should be left to cool down before checking the shims.
Is the timing ok.

Cheers

A.M.

PS see thread a few posts down "Timing 180 degrees out"

[yellowstorm]

It may be a long shot, but have you checked the fuel filter/strainer in the fuel tank. It may well be that some primer or paint may have made its way into the tank. This will gum up when in contact with the fuel and could have blocked the filter restricting the flow, thus creating fuel starvation.

[vtr9999]

tks for the advice guys, im just waiting for a stator and voltage regulator to come in before i jump back to a fuel issue again, at that point i will rebalance carbs, and set my tps

the timing has been checked and the valves were shimmed cold, when the rings were being done

the filter is clean in the tank

[Pete.L]

Rick Said

the bike cuts out intermittently at idle and while on the throttle runs good about two thirds of the time

I've had a similar occurrence in the past.
The first time was due to a sticking carb slide not returning properly and causing the bike to over fuel at low revs. This was cured with a bit of wet & dry on the slides and polishing the edges.
The Second was due to the dynojet needles wearing out the emulsion tubes in the carbs and causing them to oval. I had to re-tune the fueling. This only worked for a while and then I had to make a decision on either new carbs or a new bike.
Hope it's not the carbs.

Pete.l

[warby221]

Just a thought but is the bike stored out side?? What’s your fuel like out there for having water in it?? Do you get caught out in heavy rain???
It sounds like a problem I get every now and then with my viffer (vfr) water gets in to the tank from condensation or a slight leak in the filler cap rubber and because petrol floats on water the water sinks to the bottom of the tank were it can get sucked in to the carbs. the water forms droplets on the end of the jets and stops fuel getting through just for a second or two, then its sucked through to the engine clearing the jet. it feels like a backfire as your riding along like you just hit the front brakes for a second.
May be a good idea to put a bit of tubing on the float bowl drain and drain it in to a clear container and have a look if there’s any water in with the fuel

If this is clear then read on start with the easiest first

Since your troubles started when the tank and fairings were removed I’d start there.
Check the connections to the front coil as it’s just behind the fairing on the left front of the frame they may have been disturbed when you removed the fairing as well as the ignition pickups there’s a multi pin plug tucked away just behind the btm frame rail on the same side as the coil. There’s a big bundle of multi pin connectors at the back of the tank just under the seat give them a looking at and a clean. Check also any connectors you could have disturbed when removing the fairing pull them apart look clean then reconnect them.

For the carbs I’d strip them right down and give them a really good cleaning. Take all the jets out and blow them out with compressed air blow all the drillings and orifices in the carb bodies to.
Then reassemble them carefully checking for any oviality or binding on the slides, jets and needles also reset the float height

[vtr9999]

tks for more advice guys i appreciate it all, i will check the slides on carbs, its def not water in gas i have had tank off several times and refilled with fresh petrol if u read the post i have also changed coils and chked all wiring
maybe my carbs are pooched ill keep everyone posted

[warby221]

Well if its not any of them that I’ve mentioned im at a bit of a loss unless some one else comes up with some thing, assuming electrics and fuelling is ok then your going to have to start looking at things like broken wires and the like and there a pain to track down with an intermittent fault think its time to get a multi-meter and start checking all the wires for continuity sorry I cant be of more help

[vtr9999]

well i changed stator and voltage regulator that didnt fix it, so im on to balancing the carbs and setting the tps then i get out the sledge hammer

[Seven Of Nine Firestorm]

Just wondering also if its worth beefing up the "earth" wiring, taking them off scratching up just incase there is rust under making the electrical connections not so good.

[vtr9999]

tks i have cleaned the earth, keep ideas coming, im waiting for a carb synch gauges to come in but i am wondering if i screwed somthing up in the pair system when i had it off before anyone have any advice on the pair system?

[cupasoop]

anyone have any advice on the pair system?

Afraid your pretty much on your own with that one. Mostly UK based folk here and we didn't get the pair system, think that was reserved for the north American market. Best try the superhawk forum for info on the pair system.

Did you say when the bike is cutting out, is it doing it at idle or when you are moving? What revs/speed does it happen at?

[vtr9999]

well guys, i fitted a electric fuel pump from napa and bypassed the petcock and i synced the carbs, bike is running beautifull on stand i think the carb synching is what brought the bike back, but i do notice a big difference with an electric fuel pump if u want to get rid of any backfire or hicup when u let off the throttle fit a electric fuel pump and resynch ur carbs it will run better than knew at least mine does, i will let use know how the test ride goes,

[Pete.L]

Sounds promising
Let us know how the test ride goes.
Good Luck

Pete.l

[vtr9999]

well guys, the bike is running better than ever, i would recomend an electric fuel pump and carb synchonization to any avid vtr owner, almost all backfires are eliminated when coming off the throttle, the pump i used is 4-7psi posi-flow 12volt sold at local napa dealers for 50bucks, the bike has a whole different feel with 954 forks and brakes and the motocross handlebars i fitted are much easier on the back, these bikes are unreal i fitted a 520 sprocket and chain conversion and when going through the gears i can hardly hang on to the handlebars.
well i have to get some miles on her before the snow comes
cheers
Rick